Apparatus for perforating well casings



March 24, 1970 N. COMAN 3,502,161

- APPARATUS FOR PERFORATING WELL CASINGS Filed March 8, 1967 //;venf0r':

Nicol-cue COMAN mamw 3,502,161 APPARATUS FOR PERFORATING WELL CASINGS Nicolae Coman, Ploesti, Rumania, assignor to Ministerul Petrolului, Bucharest, Rumania, a firm Filed Mar. 8, 1967, Ser. No. 621,548 Int. Cl. E21b 43/116 U.S. Cl. 1754.57 3 Claims ABSTRACT OF THE DISCLOSURE An apparatus for perforating well casings by firing bullets therethrough. The apparatus comprises a threaded socket member which has a plurality of gun barrels, each of which is about 3 mm. in diameter. The socket member is screwed into a mating cavity of a body structure, which has a corresponding plurality of frusto-conically shaped channels, in such a way that each gun barrel is aligned with a frusto-conically shaped channel. The body structure is also formed with an ignition chamber having suitable electrical ignition means. The ignition chamber and the plurality of frusto-conically shaped channels are filled with a predetermined quantity of gun powder. The body structure, furthermore, has passage means connecting the ignition chamber and the plurality of frustoconically shaped channels. These passage means are designed and dimensioned to produce a simultaneous ejection of the bullets from the gun barrels at substantially equal velocities.

The device prevents the carrying E through the well casing of poorly consolidated sand in the oil and gas producing layers by providing a passageway through the casing.

The invention refers to an apparatus for perforating a well casing. The apparatus of this invention is adapted to produce in the casing a lot of small diameter orifices, in order to avoid sand flooding during the exploitation of poor consolidated formations.

There is already known a gun perforator type of apparatus for perforating the casing and the annular cement positioned around the casing, which has several gun tubes for small diameter bullets for producing many perforations having small flowing sections for the fluid passing into the tubing, so as to form a filter for sand flooding.

These known perforating apparatuses have the disadvantage that, having only one compartment for the gun powder, not all of the bullets are ejected with the same velocity when the explosion occurs due to various causes, so that only some of the bullets perforate the casing and the annular cement, while others are retained in the casing and may cause accidents.

This invention eliminates these drawbacks by providing the explosion chamber with several frusto-conical housings positioned behind each gun barrel in which bullets are introduced. These housings are charged with a predetermined quantity of pressed gun-powder, which is necessary for perforating the casing and the cement ring. These housings are connected to a central chamber, which is also filed with gun-powder, and in which there is disposed a round filament which is connected to the electric system for starting the blasting.

The connectnig channels between the frusto-conical housings and the central chamber, where the filament is mounted, are so dimensioned that the starting of the blasting and the ejecting of the bullets are ensured while at the same time preventing, to a great extent, the transferring of gases from one gun barrel to another.

These and other features of the present invention will become further apparent from the following detailed nite States atent description thereof, which is to be read with reference to the accompanying drawing in which there is illustrated in perspective and in partial section an embodiment of the invention.

In the body 1, having an interior thread a and a flange b, a component 2 is axially mounted. The latter is provided with nine gun barrels 3, one being placed centrally and eight in a circle around it. The component 2 is firmly attached to the body 1 by means of an annular screw 4, which is screwed into the body 1 as illustrated in the drawing and which has some orifice c adapted to receive the fastening key (not illustrated).

A frusto-conical part 5, having nine frusto-conically shaped channels d, positioned beneath and collinearly with the gun barrels 3, is fixedly mounted by securing the part 2 inside the cell 1.

The pressed gun-powder is introduced into the frustoconically shaped channels d. A tightening gasket is mounted between part 2 and the frusto-conical part 5, which prevents the fluid under pressure in the well to deleteriously affect the gun-powder, creating also simultaneously the possibility of tamping the blasting chambers.

In the body 1, under the frusto-conical part 5, a central chamber 7 is provided, which is also filled with gunpowder, and in which a filament 8 is placed, which is connected to the electric system for starting the blasting. Between the central chamber 7 and the frusto conically shaped channels d there are provided a plurality of connecting channels, which are so dimensioned that the starting of the blasting and at the same time the preventing to a large extent of the transfer of gases from one gun barrel to another is ensured.

The apparatus, according to the invention, has following advantages:

It ensures the ejecting of all the bullets with an equal velocity, so that the properly casing is well performed;

It can be easily adapted and mounted onto the currently used gun perforators in the petroleum industry.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. An apparatus for perforating well casings by firing bullets therethrough, comprising in combination:

a body structure defining an ignition chamber at the inner end thereof and defining a plurality of frustoconically shaped channels;

a gun barrel socket member, having a corresponding plurality of gun barrels, screw-threaded into said body structure so that each gun barrel is aligned with a frusto-conically shaped channel;

bullet means disposed in each barrel of said plurality of gun barrels;

electrical ignition means operatively mounted in said ignition chamber;

a predetermined amount of gun powder disposed in said ignition chamber and said plurality of frustoconically shaped channels;

said ignition chamber being positioned adjacent to and being in communication with said plurality of frustoconically shaped channels, whereby when said ignition means ignites said gun powder in said ignition chamber said bullet means are ejected from said plurality of gun barrels at substantially equal velocities, while the expanding gases produced by said gun powder are prevented to a large extent from being transferred from one gun barrel to another.

4' References Cited UNITED STATES PATENTS 493,382 3/1893 Hilder. 634,826 10/1899 Masini 10238 5 2,061,835 11/1936 Haines.

2,336,819 12/1943 Turechek 891 X SAMUEL W. ENGLE, Primary Examiner US. Cl. X.R. 10 89-l; 102-38 

